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J. HIGGINBOTTOM.

GRINDING MILL.

No. 250,245. Patented Nov. 29,1881.

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J. HIGGINBOTTOM.

GRINDING MILL.

No. 250,245. Patented Nov. 29.1881.

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UNrTno STATES PATENT FFrc JAMES HIGGIN BOTTOM, OF LIVERPOOL, OOUNTY OF LANCASTER, ENGLAND.

GRINDING-MILL.

SPECIFICATION forming part of Letters Patent No. 250,245, dated November 29, 1881.

Application filed June 17, 1881. (No model.) Patented in England November 9, 1880.

To all whom it may concern Be it known that I, JAMES HIGGINBOTTOM, of Liverpool, in the county of Lancaster and Kingdom of England, have invented certain new and useful Improvements in Grinding or Granulating Mills, (for which I have received Letters Patent in England, No. 4,589, dated November 9, 1880;) and I do hereby declare that the following is a full, clear, and exact description of the invention, which will enable others skilled in the art to which it appertains to make and use the same.

This invention consists in a peculiar arrangement and combination ot'spiral ribs and grooves for the grinding or grauulatingof grain or other material, such spiral ribs and grooves being formed on the grinding-faces of asize and pitch suitable for the material being ground or granulated. The spiral ribs and grooves are especially applicable to mills having flat or nearly flat hard close-grained surfaces.

In carrying out this invention I prefer to dispense with the angular or circular lands and furrows as now commonly used in grinding and granulating mills.

It is well understood by millers that in on dinary mills the lands and furrows on the one grinding-face cross those on the other grinding-face, when in work, at some predetermined angle, and that a scissor-like or shearing action ensues between the lands upon the two opposite grinding-faces; also, that the grinding face or faces must'revolve at such a velocity as will cause the material being ground to pass outward and between the grinding-faces by the action of centrifugal force. In any case, and with the slowest velocity it is possible to use, the shearing action of the lands and furrows produces a very violent tearing and crushing effect upon the material being ground or granulated between the faces. This violent tearing 0r shearing action is very detrimentalas, for instance, when grinding or granulating wheat, the shearing action not only causes the soft interior of the grain to become pulverized into fine white flour, but also causes the outer skin and germ of the wheat to become comminuted and commingled therewith. To obviate these grave defects I arrange spiral ribs and grooves on the grinding-faces in such a manner that as the grain passes (by the action of centrifugal force) between the grinding-faces the ribs upon one of the grinding-faces shall press with a gentle cutting or squeezing action against the ribs on the opposite grinding-face; and I also arrange the spiral ribs in such a manner as to give any desired degree of squeezing or cutting action. The result of such arrangement is, that the grain or other material becomes gently broken up into smaller pieces during its passage from the center of the grinding-facesto the periphery. This result is of great importance in the manufacture of wheat flour, because by the use of spiral ribs and grooves the soft interior of the wheat may be broken up into a granulous condition without the detrimental pulverizing of the outer skin and germ, as in ordinary mills.

The spiral ribs or grooves may be of a constant pitch, or they may be of a fine pitch and size at the periphery and gradually increasing in size and pitch toward the cen ter of the grinding-faces.

The arrangements I prefer in practice are shown on the accompanying drawings.

Figurel represents the spiral ribs and grooves arranged upon the grinding-faces for granulating wheat or other grain. Fig. 2 represents a section through the grinding-faces when in position for actual work. Fig. 3 shows the spiral ribs and grooves upon the revolving and stationary grinding-faces, together with a section across or through the ribs and grooves. Fig. 4; shows various sections ofspiral ribs and grooves suitable for granulating wheat in the various stagesof the high milling system.

The same descriptive letters apply to all the drawings.

A represents the revolving grinding-face, which is shown in the drawings to be revolving in the direction of the arrow, or with the sun, as understood by millers.

B represents the stationary grinding-face.

O D represent a spiral rib and its corresponding groove E E, formed upon the revolving grinding-face.

C D represent a spiral rib and its corresponding groove E E, formed upon the stationary grinding-face.

F O and F O are radial lines drawn through the center of the grinding-faces.

I prefer to out the spiral ribs so that when the grinding-faces are brought together and the point Oon the stationaryface is lying upon the point C on the revolving face, then the point D on the stationary face falls upon, or nearly upon, point D of the revolving face, for the purpose of preventing the scissor-like or shearing action which ensues when ordinary lands and furrows are used. I also cut the ribs 0 D and O D of such a spiral as will make the angles F O D and F O D upon the grinding-faces suitable for the material being granulated or ground. As a rule, the greater these angles are made the gentler will be the cutting or squeezing action of the spiral ribs.

In forming the spiral ribs and grooves I proceed as follows: I first prepare the plain uncut grinding-faces by an ordinary lathe or by a grinding machine or by other well-known means, in such a manner that the faces are left smooth and perfectly true. The grinding-faces may be either straight or inclined; but I prefer to make them inclined or with a downward pitch toward the center, as shown on Fig. 2, in such a manner that when placed together they touch each other at their peripheries only. The incline of the faces will depend upon the work to be done, and a suitable incline for cracking and granulatin g wheat is from threequarters to one and a quarter inch to the foot. I next place or mount the grinding-faces in a suitable lathe or machine, for the purpose of cutting the spiral ribs and grooves thereon.

The method I prefer for cutting the spiral ribs is first to mount the smooth grinding-face on an ordinary l'athe face-plate; secondly, to

apply a suitably-shaped cutting-tool to the face; thirdly, to cause the cutting-tool to travel across the grinding-face at the same time as the surfaces are revolving with or on the face-plate. By this method, which will be readily understood by an engineer, I succeed in cutting a true spiral upon the grinding-face.

The pitch of the spiral can be varied to any desired degree by causing the traverse of the cutting-tool and the movement of the grinding-surface to vary in relation to each other. I prefer to cut the spiral ribs and grooves to the shape as shown on the sections atwac; but they may be of any other form, either angular, or angular with flat tops, rounded or otherwise, and of any degree of fineness or coarseness.

For the granulating of wheat I prefer the pitch of the spiral ribs to be about as shown on the drawings at Fig. 3.

I claim as my invention 1. In a grinding-mill, the combination of two opposing grinding-surfaces, each dressed with spiral ribs and grooves lying, when in action, in substantially parallel line with the ribs and grooves of the opposite face.

2. In a grinding-mill, the combination of two opposed grinding-surfaces provided with ribs and grooves, those of each disk lying obliquely to the radius and approximately parallel to those upon the opposite grinding-surface, sub stantially as shown and described.

JAMES HIGGINBOTTOM.

Witnesses:

WM. P. THoMPsoN, OnAnLEs SOUTHALL. 

